High-frequency signaling system



June 7, 1927.

.I. F. BYRNES HIGH FREQUENCY SIGNALING SYSTEM Fild May 11, 19125 Invefitor: Irving F'. Bzr'nes, Hi5 Attrney;

latented June 7, .1927.

nuns!) STATES- IBVING I. IBYBNEB,

OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

HIGH-FREQUENCY sIeNAnm-G sys'rzam;

Application filed May 1 1, 1925. Serial. No. 29,304.

My present'invention relates to signaling systems adapted for duplex operation, and more particularly to high frequency signaling systems adapted for telephone commu- 6 nication. I

One method which has been proposed for permitting of duplex-communication by the use of a single high frequency for transmission in both directions consists in the provision of a-transmitting apparatus which is operative only when the signaling potential is impressed ther'eonand which will supply no high frequency current to the communication circuit at other times.

The object of my invention is to provide a transmitting system which will be operative only when a signaling potential is applied thereto.

The novel features which I believe to be characteristic of my invention are pointed out with particularity in the appended.

claims; my invention itself, however, both as to its organization and method of operation will best be understood by. reference to the following description taken in connection with the accompanying drawing in which I have shown diagrammatically one circuit organization which may be used in carrying my invention into effect.

I have indicated in the drawing the application of my invention to a transmitting system adapted for duplex radio telephone communication through the medium of an antenna 1. Thereceiving apparatus which may be used with the system illustrated may also be connected to the antenna 1, but apparatus for thisv purpose is not indicated as it forms no part of my present invention. A suitable apparatus for this purpose is described and claimed in aco-pending applica- .tion of Emmet F. Carter, Serial No. 7 52,243,

filed. November 25, 1924. v

The. transmitting apparatus illustrated comprises a three-electrode electron discharge tube 2, which serves as an oscillation generator, an intermediate am lifying tube 3, which serves to amplify oscillations pro-. duced bytube 2, a power amplifying tube 4, which serves to amplify oscillations delivered by amplifying tube 3, and modulating tube 5, which serves to modulate the amplified oscillations supplied by tube' 4 to the e. antenna 1, and a control tube 6 for controlling the operation of the intermediate am- 'plifying tube 3. The necessary potentials required for operating the plate circuits'of the tube equipment are supplied by a source of potential 7, which is indicated. as a battery, but which may .be any convenient source adapted to supply the different potentials required for the operation of the different tubes. v

Intermediate amplifying tube 3 is con-- nected in series with the plate circuit of control tube 6. The grid of tube 6 is biased bymeans of the.'battery 8 to a negative potential of such value that-under normal conditions substantially no "current will flow in the plate circuits of tubes 6 and 3-, and hence no high frequency currents will be supplied to the antenna, 1'. Current produced in the local circuit of microphone 9" is supplied by means of the secondary transformer windings 10 and 11 to the grid circuit of the modulator tube 5"and to the grid circuit of control tube 6. When an audio frequency signalingpotential is thus impressed on the gridl circuit of control tube- 6 the grid potential' becomes less negative, permitting current to flow in the plate circuit of intermediate amplifier'3. High frequency oscillations produced by the tube 2 T i are then supplied through the coupling con- .denser 12 tothe grid of amplifier 3, and a amplified. The amplified oscillationsare supplied by coupling condenser 13 to the.

grid of the power amplifier tube 4. The amplified oscillations set up in the plate or'output circuit oftube 4 are modulated by the action of tube 5 in a well known manner, and thus modulated high frequency oscillations are supplied to the antenna 1 as long as signaling current is supplied by the micro-.

source of high frequency oscillations, an.

amplifying tube having aplate circuit which includes an impedance of such value that. normally substantially no current will flow supplied to the antenna 1. Thus, there will therein, means for supplying high frequency oscillations from said source to the grid of said amplifier tube, means for lowering said impedancein response to signaling potential sufliciently to permit current to flow in the plate circuit of the amplifier,

and means acting independently of said impedance for modulating the amplified high frequency currents.

2. A transmitting apparatus for a high frequency signaling system comprising a source of high frequency oscillations, an

'-electron discharge amplifierhavinga plate .the amplifier, and means *acting independently of said impedance for modulating the amplified high frequency currents.-

3. A transmitting apparatus for a high frequency signaling system comprising a source of high frequency oscillations, an electron dischargeamplifier having included in its plate circuit a three-electrode electron discharge device having its grid potential I normally of such value that substantiall no current will How in the ,plate circuit 0 the amplifier, means for supplying high frequency oscillations from said source tothe grid of said amplifier, means responsive to a signaling potential for permitting current to flow in the plate circuit of the amplifier and means acting independently of said three-electrode device for modulating the amplified high frequency oscillations.

4. A transmitting apparatus for a high frequency signaling system comprising a source of highfrequency osc1liat1ons,'an

electron discharge amplifier having included in its plate circuit a three-electrode electron discharge device. having its grid potential normally of such value that substantiall no current will flow in the plate circuit 0 the oscillator, means for supplying high frequency oscillations from-said source "to. the

gridof said amplifier, means for impressing a signalingpotentialupon the grid of the electron discharge device and thereby per mitting current to flow in the plate circuit of the amplifier, and means acting independently of said three-electrode device for I modulating oscillations. I

5. The combination in a high frequency signaling system of a transmitting apparatus comprising a source of high frequency oscillations, an electron discharge amplifier for amplifying oscillations produced by sand of said amplifier, a three-tlectrode electron discharge modulator forvmodulating the amplified oscillations, and means for s1multaneously impressing a signaling potential upon the grids of said control device and said modulator for rendering the amplifier operative to amplify high frequency oscillations supplied by said source and modulating theamplified oscillations.

In witness whereof, I have hereunto set my hand this 9th day of May, 1925.

IRVINGIYF. BYRNES.

the amplified high frequency.

, source, a three-electrode electron discharge f control device for controlling the operation 7 

